IL185134A

IL185134A - Mechanical vibration deicing system

Info

Publication number: IL185134A
Application number: IL185134A
Authority: IL
Original assignee: Amihay Gornik
Priority date: 2007-08-08
Filing date: 2007-08-08
Publication date: 2013-10-31
Also published as: US20110210207A1; WO2009019696A3; US8517313B2; US20130299638A1; WO2009019696A2; IL185134A0

Abstract

An aircraft deicing system including at least one motor operative to drive at least one eccentric mass in rotational motion and at least one displacer coupled to at least one location on at least one aircraft surface and coupled to the at least one eccentric mass such that forces produced by the rotational motion of the eccentric mass are applied to the at least one displacer, causing the at least one displacer to displace the at least one aircraft surface in a plurality of directions at each of the at least one location, thereby causing disengagement of ice from the at least one aircraft surface.

Description

πυυη JV.DO rrwon Τ ΧΏ MECHANICAL VIBRATION DEICING SYSTEM AMICHAI GORNIK C: 61951 61951 v2 8/8/07 FIELD OF THE INVENTION The present invention relates to deicing systems and methodologies particularly suited for aircraft and to aircraft employing such deicing systems and methodologies.

BACKGROUND OF THE INVENTION The following publications are believed to represent the current state of the art: U.S. Patents 2,037,626; 2,135,1 19; 2,297,951; 2,201,155; 3,549,964; 3,672,610; 3,779,488; 3,809,341; 4,875,644; 4,399,967; 4,458,865; 4,501,398; 5,206,806 and 7,084,553.

SUMMARY OF THE INVENTION The present invention seeks to provide a highly efficient deicing system and methodology particularly suitable for aircraft and aircraft employing such deicing systems and methodologies.

There is thus provided in accordance with a preferred embodiment of the present invention an aircraft deicing system including at least one motor operative to drive at least one eccentric mass in rotational motion and at least one displacer coupled to at least one location on at least one aircraft surface and coupled to the at least one eccentric mass such that forces produced by the rotational motion of the eccentric mass are applied to the at least one displacer, causing the at least one displacer to displace the at least one aircraft surface in a plurality of directions at each of the at least one location, thereby causing disengagement of ice from the at least one aircraft surface.

There is also provided in accordance with another preferred embodiment of the present invention an aircraft including an airframe including at least one aircraft surface, at least one motor operative to drive at least one eccentric mass in rotational motion and at least one displacer coupled to at least one location on at least one aircraft surface and coupled to the at least one eccentric mass such that forces produced by the rotational motion of the eccentric mass are applied to the at least one displacer, causing the at least one displacer to displace the at least one aircraft surface in a plurality of directions at each of the at least one location, thereby causing disengagement of ice from the at least one aircraft surface.

Preferably, the at least one displacer is operative in a cyclic manner, wherein in each cycle the at least one displacer is operative to displace the at least one aircraft surface in a plurality of directions at each of the at least one location. Additionally or alternatively, the aircraft deicing system also includes at least one ice thickness sensor for sensing an ice thickness responsive characteristic of the at least one aircraft surface and at least one controller responsive to an output of the ice thickness sensor indicating the ice thickness responsive characteristic of the at least one aircraft surface for selecting a rotational speed of the at least one motor.

Preferably, the at least one motor drives the at least one eccentric mass in rotational motion about a first axis and at least a portion of at least one of the at least one eccentric mass is selectably displaceable along a second axis generally perpendicular to the first axis.

There is further provided in accordance with yet another preferred embodiment of the present invention an aircraft deicing system including at least one ice thickness sensor for sensing an ice thickness responsive characteristic of at least one aircraft surface, at least one selectably controllable ice disengager operative to cause ice to disengage from the at least one aircraft surface and at least one controller responsive to an output of the ice thickness sensor indicating the ice thickness responsive characteristic of the at least one aircraft surface for varying at least frequency of the selectably controllable ice disengager.

Preferably, the at least one selectably controllable ice disengager includes at least one motor operative to drive at least one eccentric mass in rotational motion and at least one displacer coupled to at least one location on at least one aircraft surface and coupled to the at least one eccentric mass such that forces produced by the rotational motion of the eccentric mass are applied to the at least one displacer, causing the at least one displacer to displace the at least one aircraft surface in a plurality of directions at each of the at least one location, thereby causing disengagement of ice from the at least one aircraft surface. Additionally, the at least one displacer is operative in a cyclic manner, wherein in each cycle the at least one displacer is operative to displace the at least one aircraft surface in a plurality of directions at each of the at least one location.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: Fig. 1 is a simplified illustration of an aircraft including a deicing system constructed and operative in accordance with a preferred embodiment of the present invention; Fig. 2 is a simplified exploded view illustration of part of a preferred embodiment of a deicing system suitable for use in the aircraft of Fig. 1 ; Figs. 3A, 3B, 3C and 3D illustrate four typical stages in a rotation cycle which drives a displacer coupled to an aircraft surface in a deicing system of the type shown in Figs. 1 and 2; Figs. 4A, 4B, 4C and 4D illustrate, in exaggerated form, deformation of an aircraft surface responsive to operation of the deicing system of Figs. 1 & 2 at stages corresponding to those shown in Figs. 3A, 3B, 3C and 3D, respectively; Fig. 5 is a simplified flow chart illustrating one embodiment of control functionality employed in the deicing system of Figs. 1 - 4D; Figs. 6A and 6B, taken together, are a simplified flow chart illustrating another embodiment of control functionality employed in the deicing system of Figs. 1 -4D; and Fig. 7 is a graphical illustration useful in understanding the control functionalities of Figs. 5 and 6A-6B.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Reference is now made to Fig. 1, which is a simplified illustration of an aircraft including a deicing system constructed and operative in accordance with a preferred embodiment of the present invention and to Fig. 2, which is a simplified exploded view illustration of part of a preferred embodiment of a deicing system suitable for use in the aircraft of Fig. 1.

As seen in Fig. 1, there is provided an aircraft 100 equipped with a deicing system constructed and operative in accordance with a preferred embodiment of the present invention. The deicing system is preferably located within the wings 102 of the aircraft adjacent the leading edges 104 of the wings 102.

It is a particular feature of the present invention that the deicing system includes at least one motor operative to drive at least one eccentric mass in rotational motion and at least one displacer coupled to at least one location on at least one aircraft surface, preferably the leading edge 104 of a wing 102, and coupled to the at least one eccentric mass such that forces produced by the rotational motion of the eccentric mass are applied to the at least one displacer, causing the at least one displacer to displace the at least one aircraft surface in a plurality of directions at each of the at least one location, thereby causing disengagement of ice 106 from the at least one aircraft surface.

In the illustrated embodiment, a motor 110, preferably an electric motor, is disposed interiorly of each wing 102 adjacent the leading edge 104 thereof and preferably alongside the aircraft fuselage 1 12. A drive shaft 114 couples each motor 110, such as a model 3863012C, manufactured by Faulhaber GmbH of Daimlerstrasse 23, 71101 Schonaich, Germany, to a series of displacer assemblies 116. It is appreciated that alternatively multiple motors 110 and multiple drive shafts may each be coupled to a series of displacer assemblies 116 at various locations within each wing.

Turning now particularly to Fig. 2, it is seen that each displacer assembly 1 16 includes an elongate drive shaft portion 120, preferably having flattened portions 122 and 124 at ends thereof and a flattened portion 126 generally central thereof. Flattened portions 122 and 124 of elongate drive shaft portion 120 are secured as by respective set screws (not shown) to respective first ends 128 and 130 of flexible couplings 132 and 134. Flexible couplings 132 and 134 may be any suitable flexible couplings, such as model C076A-5M manufactured by Berg W.M., Inc. of 499 Ocean Avenue, East Rockaway, NY 1 1518 USA. Respective second ends 138 and 140 of flexible couplings 132 and 134 are preferably secured as by respective set screws (not shown) to corresponding flattened ends of drive shaft elements (not shown) which interconnect the various displacer assemblies 1 16 to each other and to motor 1 10.

A pair of ball bearings 150 and 152, such as Model 34-5, commercially available from Schaeffler Group - FAG GmbH of Industriestrasse 1-3, Herzogenaurach 91074, Germany, are pressure fit mounted onto drive shaft portion 120 between flattened portion 126 and flattened portions 122 and 124, respectively. A leading edge attachment element 160 is mounted onto drive shaft portion 120 via ball bearings 150 and 152 which engage respective bearing receiving apertures 162 and 163 formed in respective arms 164 and 165 and are fixed thereto by respective lock washers 166 and 167 and wave spring washers 168 and 169. Leading edge attachment element 160 includes a leading edge attachment portion 170, preferably integrally formed with arms 164 and 165 and having a curved interior leading edge attachment surface 172 which is fixedly adhered, as by an adhesive, such as product no. 4132 Structural Adhesive Kit, commercially available from 3M, St. Paul, Minnesota 55144, USA, to a correspondingly curved interior surface of leading edge 104 of wing 102.

An eccentric drive mass 180 is preferably fixedly mounted to elongate drive shaft portion 120 for rotation together with drive shaft portion 120 about an axis 182. The eccentric drive mass 180 is preferably fixedly mounted to elongate drive shaft portion 120 at flattened portion 126 by means of a pair of suitably configured bracket elements 184 and 186 having respective facing recesses 188 and 190 having cross sectional configurations which respectively match the cross sectional configuration of the drive shaft portion 120 at flattened portion 126. Respective ends 192 and 194 of bracket elements 184 and 186 are retained within a suitable socket 196 of eccentric drive mass 180 by means of a retaining pin 198.

Preferably bracket elements 184 and 186 are held in place by a pair of screws 200 and corresponding nuts 202, washers 204 and lock washers 206.

An acceleration sensor 210, such as a model NMA 1213D commercially available from Freescale Semiconductors Inc., 6501 William Cannon Drive West, Austin, Texas 78735, USA, is preferably mounted on at least one displacer assembly 1 16 on each wing of the aircraft in order to serve as an ice thickness sensor, as is described hereinbeiow. A variable speed motor 212 having a mass 214 eccentrically mounted on an output shaft 216 thereof is mounted on the same displacer assembly 1 16.

A deicer controller 220 preferably receives inputs from acceleration sensors 210 associated with the various displacer assemblies 1 16 and provides control inputs to motor 1 10. The control logic preferably employed by deicer controller 220 is described hereinbeiow with reference to Fig. 5.

According to an alternative embodiment of the present invention, an example of which is illustrated in an enlargement 230 in Fig. 2, some or all of mass 180 may be selectably displaced along an axis 231, generally perpendicular to axis 182, such that the effective distance of the mass 180 from axis 182 may be varied. This provides an additional degree of freedom in controlling the operation of the deicing system of the present invention. In the illustrated embodiment shown in enlargement 230, a part 232 of mass 180 is mounted on a screw drive 234, which may be driven by a motor 236 to adjust the positioning of part 232 of mass .180 along axis 231.

It is appreciated that flexible couplings 132 and 134 are provided so that the force applied by mass 180 during rotation thereof is applied to leading edge 104 through leading edge attachment element 160 rather than through drive shaft 114 to other displacer assemblies 116.

Reference is now made to Figs. 3A, 3B, 3C and 3D, -which illustrate four typical stages in a rotation cycle which drives a displacer coupled to an aircraft surface in a deicing system of the type shown in Figs. 1 and 2, and to Figs. 4A, 4B, 4C and 4D, which illustrate, in exaggerated form, deformation of an aircraft surface responsive to operation of the deicing system of Figs. 1 & 2 at stages corresponding to those shown in Figs. 3A, 3B, 3C and 3D respectively.

As seen in Fig. 3A, an eccentric drive mass 380 of displacer assembly 382 is located along an axis 384 which passes through axis 182 (Fig. 2) and extends generally perpendicular to the plane defined by the tangent 386 to the curved surface 388 of a leading edge 390 to which curved interior leading edge attachment surface 392 of displacer assembly 382 is attached. Inasmuch as mass 380 lies beyond axis 182 with respect to surface 388, the displacer assembly 382 is applying a pull force to the leading edge 390 along axis 384.

As also seen in Fig. 3A, eccentric drive mass 400 of displacer assembly 402 is located along an axis 404 which passes through axis 182 (Fig. 2) and extends generally parallel to the plane defined by the tangent 406 to the curved surface 408 of leading edge 390 to which curved interior leading edge attachment surface 412 of displacer assembly 402 is attached. Inasmuch as mass 400 lies along an axis which is not perpendicular to surface 408, the displacer assembly 402 is applying a bending force to the leading edge 390.

Fig. 4A shows, in an exaggerated manner the deformation of the leading edge 390 corresponding to the operational state illustrated in Fig. 3A. The extent of exaggeration is estimated to be x 40.

In Fig. 3B, eccentric masses 380 and 400 have been rotated from the position seen in Fig. 3A. As seen in Fig. 3B, eccentric drive mass 380 of displacer assembly 382 is not located along axis 384. Inasmuch as mass 380 lies along an axis which is not perpendicular to surface 388, the displacer assembly 382 is applying a bending force to the leading edge 390.

As also seen in Fig. 3B, eccentric drive mass 400 of displacer assembly 402 is not located along an axis 404 but is nearly perpendicular to axis 404. Inasmuch as mass 400 lies between axis 182 and surface 406, the displacer assembly 402 is applying a push force to the leading edge 390.

Fig. 4B shows, in an exaggerated manner the deformation of the leading edge 390 corresponding to the operational state illustrated in Fig. 3B. The extent of exaggeration is estimated to be x 40.

In Fig. 3C, eccentric masses 380 and 400 have been rotated approximately 180° from the position seen in Fig. 3A. As seen in Fig. 3C, eccentric drive mass 380 of displacer assembly 382 is located along axis 384 which passes through axis 182 (Fig. 2) and extends generally perpendicular to the plane defined by tangent 386 to curved surface 388. Inasmuch as mass 380 lies between axis 182 and surface 388, the displacer assembly 382 is applying a push force to the leading edge 390 along axis 384.

As also seen in Fig. 3C, eccentric drive mass 400 of displacer assembly 402 is located along axis 404 which passes through axis 1 82 (Fig. 2) and extends generally parallel to the plane defined by tangent 406 to curved surface 408. Inasmuch as mass 400 lies along an axis which is not perpendicular to surface 408, the displacer assembly 402 is applying a bending force to the leading edge 390.

Fig. 4C shows, in an exaggerated manner the deformation of the leading edge 390 corresponding to the operational state illustrated in Fig. 3C. The extent of exaggeration is estimated to be x 40.

In Fig. 3D, eccentric masses 380 and 400 have been rotated further counterclockwise, as seen from the perspective of the sectional illustration shown along lines A-A therein, from the position seen in Fig. 3A. As seen in Fig. 3D, eccentric drive mass 380 of displacer assembly 382 is not located along axis 384. Inasmuch as mass 380 lies along an axis which is not perpendicular to surface 388, the displacer assembly 382 is applying a bending force to the leading edge 390.

As also seen in Fig. 3D, eccentric drive mass 400 of displacer assembly 402 is not located along an axis 404 but is nearly perpendicular to axis 404. Inasmuch as mass 400 lies beyond axis 182 with respect to surface 406, the displacer assembly 402 is applying a pull force to the leading edge 390.

Fig. 4D shows, in an exaggerated manner the deformation of the leading edge 390 corresponding to the operational state illustrated in Fig. 3D. The extent of exaggeration is estimated to be x 40.

Reference is now made to Fig. 5, which is a simplified flow chart illustrating control functionality employed in the deicing system of Figs. 1 - 4D, and to Fig. 7. As seen in Fig. 5, a control signal is preferably supplied by controller 220 to motors 212, causing the motors 212 to accelerate from rest to 500 revolutions/second. Acceleration sensors 210 measure acceleration and provide corresponding output indications to controller 220. Controller 220 calculates vibration amplitude vs. rate of rotation, which represents the frequency response of the leading edge 104 of wing 102 at which the sensor 210 is located. Fig. 7 illustrates examples of empirically derived frequency response curves for various thicknesses of ice on the leading edge 104 of wing 102. Alongside each frequency response curve of Fig. 7 is an indication, as an example, of the ice thickness represented thereby.

The controller 220 extracts the frequency at which the leading edge 104 is at resonance and, based on this frequency, calculates the amount of ice 106 present on the leading edge 104. Additionally, based on prior calibration, the controller 220 makes a determination as to whether the ice 106 present on the leading edge 104 has at least a predetermined minimum thickness, typically 2mm. If so, the controller 220 then employs a look-up table which indicates, for the thickness of ice 106 present on the leading edge 104, a desired vibration amplitude that should be applied to the leading edge 104 to break the ice 106.

Prior to operating motors 1 10, the controller 220 calculates the desired frequency of vibration corresponding to the desired vibration amplitude and makes a determination of whether, once the ice 106 is removed, the vibration amplitude will increase or decrease. Only if at the desired frequency of vibration corresponding to the desired vibration amplitude, the vibration amplitude will decrease once the ice 106 is removed, are motors 1 10 operated to drive displacer assemblies 1 16 to remove the ice 106 from the leading edges 104 of wings 102. Otherwise, the thickness of the ice 106 will be allowed to increase until, at the desired frequency of vibration corresponding to the desired vibration amplitude, the vibration amplitude will decrease once the ice 106 is removed.

The functionality of Fig. 5 preferably takes place intermittently at predetermined intervals, typically 10 minutes. The operation of motors 1 10 preferably takes place upon each actuation for a predetermined number of revolutions, typically 100 revolutions. Alternatively, the cycle of operation described hereinabove is repeated intermittently at intervals which depend on the altitude and flying conditions of the aircraft. Additionally or alternatively, the cycle of operation described hereinabove is repeated intermittently at intervals which depend on the thickness of the ice 106 present on the leading edge 104.

Reference is now made to Figs. 6A and 6B, which, taken together, are a simplified flow chart illustrating alternative control functionality which may be employed in the alternative embodiment of deicing system of Figs. 1 - 4D when some or all of mass 180 may be selectably displaced along axis 231 such that effective distance of the mass 180 from axis 182 may be varied.

As seen in Figs. 6A and 6B, and similarly to the functionality of Fig. 5, a control signal is preferably supplied by controller 220 to motors 212, causing the motors 212 to accelerate from rest to 500 revolutions/second. Acceleration sensors 210 measure acceleration and provide corresponding output indications to controller 220. Controller 220 calculates vibration amplitude vs. rate of rotation, which represents the frequency response of the leading edge 104 of wing 102 at which the sensor 210 is located.

Prior to operating motors 110, the controller 220 calculates the desired frequency of vibration corresponding to the desired vibration amplitude and makes a determination of whether, once the ice 106 is removed, the vibration amplitude will increase or decrease. Only if at the desired frequency of vibration corresponding to the desired vibration amplitude, the vibration amplitude will decrease once the ice 106 is removed, are motors 1 10 operated to drive displacer assemblies 1 16 to remove the ice 106 from the leading edges 104 of wings 102.

At this stage, as distinguished from the functionality of Fig. 5, the eccentric mass 180 is positioned along axis 231 so as to be close to axis 182 such that the force applied by rotation of mass 180 is minimized until such time as the rotational frequency of motor 110 reached the desired frequency. Once the rotational frequency of motor 110 reaches the desired frequency, the eccentric mass 180 is displaced outwardly along axis 231 so as to increase the force applied by rotation thereof about axis 182.

The functionality of Figs. 6A and 6B preferably takes place intermittently at predetermined intervals, typically 10 minutes. Alternatively the cycle of operation described hereinabove is repeated intermittently at intervals which depend on the altitude and other flying conditions of the aircraft. Additionally or alternatively, the cycle of operation described hereinabove is repeated intermittently at intervals which depend on the thickness of the ice 106 present on the leading edge 104.

The operation of motors 1 10 preferably takes place upon each actuation for a predetermined number of revolutions, typically 100 revolutions. Furthermore, once motors 1 10 are deactuated, the eccentric mass 180 is immediately displaced along axis 231 so as to be close to axis 1 82 so as to immediately minimize the force applied by rotation thereof as motors 1 10 decelerate to rest.

It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the present invention includes both combinations and subcombinations of various features described herein and improvements and variations which would occur to persons skilled in the art upon reading the foregoing description and which are not in the prior art.

Claims

1. An aircraft deicing system comprising: at least one motor operative to drive at least one eccentric mass in rotational motion; and at least one displacer coupled to at least one location on at least one aircraft surface and coupled to said at least one eccentric mass such that forces produced by said rotational motion of said eccentric mass are applied to said at least one displacer, causing said at least one displacer to displace said at least one aircraft surface in a plurality of directions at each of said at least one location, thereby causing disengagement of ice from said at least one aircraft surface.

2. An aircraft deicing system according to claim 1 and wherein said at least one displacer is operative in a cyclic manner, wherein in each cycle said at least one displacer is operative to displace said at least one aircraft surface in a plurality of directions at each of said at least one location.

3. An aircraft deicing system according to claim 1 or claim 2 and also comprising: at least one ice thickness sensor for sensing an ice thickness responsive characteristic of said at least one aircraft surface; and at least one controller responsive to an output of said ice thickness sensor indicating said ice thickness responsive characteristic of said at least one aircraft surface for selecting a rotational speed of said at least one motor.

4. An aircraft deicing system according to any of claims 1-3 and wherein said at least one motor drives said at least one eccentric mass in rotational motion about a first axis and at least a portion of at least one of said at least one eccentric mass is selectably displaceable along a second axis generally perpendicular to said first axis.

5. An aircraft comprising: an airframe including at least one aircraft surface; at least one motor operative to drive at least one eccentric mass in rotational motion; and at least one displacer coupled to at least one location on at least one aircraft surface and coupled to said at least one eccentric mass such that forces produced by said rotational motion of said eccentric mass are applied to said at least one displacer, causing said at least one displacer to displace said at least one aircraft surface in a plurality of directions at each of said at least one location, thereby causing disengagement of ice from said at least one aircraft surface.

6. An aircraft according to claim 5 and wherein said at least one displacer is operative in a cyclic manner, wherein in each cycle said at least one displacer is operative to displace said at least one aircraft surface in a plurality of directions at each of said at least one location.

7. An aircraft according to claim 5 or claim 6 and also comprising: at least one ice thickness sensor for sensing an ice thickness responsive characteristic of said at least one aircraft surface; and at least one controller responsive to an output of said ice thickness sensor indicating said ice thickness responsive characteristic of said at least one aircraft surface for selecting a rotational speed of said at least one motor.

8. An aircraft according to any of claims 5-7 and wherein said at least one motor drives said at least one eccentric mass in rotational motion about a first axis and at least a portion of at least one of said at least one eccentric mass is selectably displaceable along a second axis generally perpendicular to said first axis.

9. An aircraft deicing system comprising: at least one ice thickness sensor for sensing an ice thickness responsive characteristic of at least one aircraft surface; at least one selectably controllable ice disengager operative to cause ice to disengage from said at least one aircraft surface; and at least one controller responsive to an output of said ice thickness sensor indicating said ice thickness responsive characteristic of said at least one aircraft surface for varying at least frequency of said selectably controllable ice disengager.

10. An aircraft deicing system according to claim 9 and also wherein said at least one selectably controllable ice disengager comprises: at least one motor operative to drive at least one eccentric mass in rotational motion; and at least one displacer coupled to at least one location on at least one aircraft surface and coupled to said at least one eccentric mass such that forces produced by said rotational motion of said eccentric mass are applied to said at least one displacer, causing said at least one displacer to displace said at least one aircraft surface in a plurality of directions at each of said at least one location, thereby causing disengagement of ice from said at least one aircraft surface.

11. An aircraft deicing system according to claim 10 and wherein said at least one displacer is operative in a cyclic manner, wherein in each cycle said at least one displacer is operative to displace said at least one aircraft surface in a plurality of directions at each of said at least one location. For the Applicant, Sanford T. Colb & Co. Advocates & Patent Attorneys C: 61951